Flexible abrasive wheel and method of making



Nov. 12, 1968 R. P. SNYDER 3,410,034

FLEXIBLE ABRASIVE WHEEL AND METHOD OF MAKING Filed Feb. 28, 1966INVENTOR 7 ROBERT P SNYDER Batman, leaumm 6 ddaaullafl A T TORNEVSUnited States Patent FLEXIBLE ABRASIVE WHEEL AND METHOD OF MAKING RobertP. Snyder, 247 Snow Sh, Saginaw, Mich. 48602 Filed Feb. 28, 1966, Ser.No. 530,709 17 Claims. (Cl. 51336) ABSTRACT OF THE DISCLOSURE A flexibleabrasive wheel having a plurality of abrasive strips arranged to form anannulus having on each side thereof between the inner and outerperipheries of the annulus an adhesive roving wound upon itself to forma ring, the convolutions being wound under tension such as to cause theadhesive to be forced between adjacent abrasive strips whereby thestrips are bonded to one another and to the ring.

This invention relates to flexible abrasive wheels and to methods oftheir manufacture, and more particularly to a flexible abrasive wheel ofsimplified construction wherein a plurality of individual abrasiveleaves or strips is arranged and held in annular form.

An object of the invention is to provide a flexible abrasive wheel ofgreatly simplified construction, and which sacrifices none of theadvantageous characteristics of flexible abrasive wheels of morecomplicated constructions.

Another object of the invention is to provide a method of making aflexible abrasive wheel of the character described and which isconsiderably more economical and rapid than methods heretofore in use.

A further object of the invention is to provide a flexible abrasivewheel construction which readily lends itself to simplified productiontechniques requiring little or no skilled labor.

Other objects and advantages of the invention will be pointed outspecifically or will become apparent from the following description whenit is considered in conjunction with the appended claims and theaccompanying drawings, in which:

FIGURE 1 is a transverse sectional view of an abrasive wheel formed inaccordance with the invention and prior to the disassembly of the wheelfrom supporting apparatus used in the manufacture of the wheel;

FIGURE 2 is a diagrammatic view illustrating the process ofmanufacturing the wheel;

FIGURE 3 is an exploded, fragmentary perspective view of a wheel andillustrating a preliminary stage in the assembly of the individualabrasive strips;

FIGURE 4 is a perspective view of a modified abrasive strip; and

FIGURE 5 is an elevational view of a completed abrasive wheel, on areduced scale.

An abrasive wheel constructed in accordance with the invention iscomposed of a plurality of strips or leaves 1 of generally rectangularconfiguration, at least one surface of each of which has an abrasivesurface 2. Initially, the strips 1 are independent of one another butare adapted to be assembled to form an annulus 3 having a central axisof rotation from which each of the leaves extends radially and with theabrasive surface of each strip facing in the same direction.

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To form the annulus 3, a cylindrical form or disk 4 may be placed on anysuitable support (not shown) and around which is looped an anchor member5 such as a Wire, cord, strap, or the like. The drawstring wire 5 isthreaded through an opening formed in each of the leaves 1. In nearlyall of the leaves 1 the opening is merely a round opening 6, but in someof the leaves the openings may comprise slots 7 extending outwardly fromthe radially inner ends of such leaves for a purpose presently to beexplained.

When sufiicient leaves 1 have been threaded on the anchor member 5 toform substantially a complete annulus, the opposite ends of the anchormember 5 are joined together in a suitable manner such as by twisting,indicated at 8, or by knotting them, and the twisted or knotted endsarranged so as to project radially outwardly. Those filler leaves 1 inwhich the slots 7 are formed then may be assembled radially with theother leaves and with the twisted ends 8 accommodated in the slots 7,thereby completing the annulus 3.

While the foregoing method of forming the annulus is preferred andclaimed as novel, it would be possible to secure the opposite ends ofthe anchor member 5 in other ways. For example, the two ends of the wireor strap could be overlapped and spot welded to one another, in whichcase leaves 1a provided with notches 8a open to one side thereof couldbe assembled with the remaining leaves so as to accommodate theoverlapped ends of the wire or strap in the notches 8a.

Following the assembly of the leaves into annular form, a pair of sideplates 9 is applied to opposite sides of the annulus. A retaining plate10 is placed in face-to-face engagement with each of the members 9, andthe entire assembly is clamped together by means of a bolt 11 whichpasses through the disk 4 and through each of the plates 9 and 10, theends of the bolt being threaded for the accommodation of nuts 12.

As is best shown in FIGURES 1 and 3, the diameter of each plate 9 whichpreferably is fabricated of a plastic such as Teflon or polyethylene, isgreater than the diameter of the disk 4 so that the peripheral edge ofeach plate 9 overlies the radially inner end of each leaf 1.- Thediameter of each plate 10 is greater than the diameter of the plates 9so that the peripheral edge of each plate 10 extends beyond theperipheral edge of each plate 9 and parallels the side edges of theleaves 1. An annular space is thus provided between the inner surface ofeach plate 10 and the adjacent side edge of the leaves 1. Preferably,the inner surface of each plate 10 at its outer end is tapered orbeveled as at 13.

Following the assembly of the leaves 1 with the holding members 4, 9,10, 11 and 12, and the clamping of the plates 9 and 10 against theleaves, the anchor member 5 may be cut and removed, but this is notessential. If desired, more than one anchor member 5 may be provided,but this, too, is not essential.

Following the assembly of the leaves and the holding means, the assemblymay be supported on a conventional mandrel (not shown) for rotationabout the axis of the annulus 3. Adjacent the mandrel is a drum or spoolof continuous filamentary material such as fiber glass roving, theleading end of a strand 15 of which may be introduced to the spacebetween one of the plates 10 and the annulus 3 in such manner thatrotation of the annulus 3 counterclockwise as viewed in FIGURE 2 willcause the strand 15 to be Wound upon itself to form a ring 16 having anaxial width corresponding to the distance between the annulus 3 and theinner surface of the adjacent plate and having a radial thicknesscorresponding substantially to the difference in the radii between theplates 9 and It The roving used may be that manufactured by OwensCorning Fiberglas Company and designated 825-60 end. It may comprise 60side by side strands of 204 side by side filaments each, the filamentsor fibers being in the nature of .0003.0004" in diameter, and suitablebinding agents being employed to maintain the roving as a unitary body.If the leaves 1a are used, the radial length of the ring 16 should begreater than the radial length of the notch 8 so that the latter may bewholly within the confines of the ring.

The strand preferably is coated with an adhesive or binding agent priorto being wound to form the ring 16. The adhesive coating can be appliedin any one of a number of ways, such as by passing the strand aroundpulleys 17, 18, and 19 which are so arranged as to cause the strand topass through a liquid adhesive 20 contained in a tank 21. The adhesivelycoated strand 15 is then Wound upon itself to form the ring 16.Successive convolutions of the strand 15 will be bonded to each otherand to the adjacent side edges ofthe leaves 1. Preferably, the tensionon the strand 15 during winding of the ring 16 will be such as to causethe adhesive to be squeezed whereupon it may penetrate between adjacentleaves 1 to a depth of about inch. Such tensioning of the strand 15 maybe assured by a pair of relatively movable, spring pressed blocks 22 and23 mounted on suitable supports 24 and 25, respectively, and in snubbingengagement with the strand Following winding of a ring 16 at one side ofthe annulus 3, the latter, together with the holding members, may bereversed in the mandrel so as to wind a similar ring 16 at its oppositeside. Alternatively, both rings 16 may be wound simultaneously from twospools 14.

Upon completing the winding of the two retaining rings 16, the assemblymay be removed from the mandrel and the adhesive permitted to cure. Thecuring procedure will depend upon the kind of adhesive utilized. Heatingwill speed up the process. In the preferred embodiment, the adhesivecomprises a polyester resin catalyzed with methyl ethyl ketone peroxide.One suitable polyester resin is that designated MR 37 CX and distributedby Cadillac Plastic & Chemical Company. It will be understood, however,that other resins, such as epoxy and phenolic, can be used in lieu ofpolyesters.

[t is not essential that the roving be passed through a bath of liquidadhesive. The Minnesota Mining & Manufacturing Company currentlymanufactures an epoxy resin impregnated glass fiber roving which isactivated and cured by heating. This roving can be wound to form therings 16 and the assembly subsequently cured according to thespecifications of the roving manufacturer so as to bond the convolutionsof the roving to one another and to the leaves 1.

Following the curing of the rings 16, the plates 9 and 10 may be removedfrom the assembly. To facilitate removal of the plates 9 and 10, theplates 9 preferably are formed of polytetrafluoroethylene and the plates10 preferably are wax-coated steel.

The abrasive wheel, consisting of the annular pack of leaves 1, therings 16, and the anchor wire 5 (if the latter has not previously beenremoved) may be clamped in a conventional manner on a rotatable arborfor use. The flaps or strips are bonded on each side to a ring ofcontinuously wound fiber glass roving impregnated with cured resin andwill have the strength to best resist the centrifugal forces of therotating wheel.

If desired, the disk 4 may be removed from the center of the annulus 3after the anchor member 5 is secured.

That is, the disk 4 is not essential in the manufacture of the abrasivewheel after the annulus of leaves has been formed. Moreover, theradially inner ends of the leaves could be painted or coated with theadhesive, if desired, but such process is not essential.

The foregoing disclosure is representative of presently preferredmethods and apparatus but is intended to be illustrative rather thandefinitive of the invention. The invention is defined in the claims.

I claim:

1. A flexible abrasive wheel comprising a plurality of abrasive stripsassembled to form an annulus; filamentary material wound upon itself toform a ring between the inner and outer peripheries of said annulus; andadhesive means bonding convolutions of said filamentary material to oneanother and to said strips between the inner and outer peripheries ofsaid annulus.

2. The construction set forth in claim 1 wherein a ring of saidfilamentary material is bonded to each side of said wheel.

3. The construction set forth in claim 1 wherein each of said strips hasan Opening therein, and including anchor means accommodated in each ofsaid openings for maintaining said strips assembled prior to their beingbonded to said ring.

4. The construction set forth in claim 1 where said annulus has an axisof rotation and said ring is coaxial therewith.

5. The construction set forth in claim 3 wherein said anchor meanscomprises a Wire-like member having its opposite ends joined together toform a closed ring, and wherein the openings in the strips adjacent thejuncture of said opposite ends are such as to enable assembly anddisassembly of said adjacent strips with and from said member followingthe joining of its said opposite ends.

6. The construction set forth in claim 5 wherein the openings in saidadjacent strips extend from the radially inner end thereof toward butterminate short of the radially outer end thereof.

7. The construction set forth in claim 5 wherein the openings in saidadjacent strips extend from one side edge thereof but terminate short ofthe opposite edge thereof, the radial length of each of such openingsbeing less than the radial width of said ring and being located withinthe confines thereof.

8. The construction set forth in claim 1 wherein said filamentarymaterial comprises continuous glass fiber roving.

9. The construction set forth in claim 1 wherein said adhesive meanscomprises a resin of the class comprising polyester, epoxy and phenolic.

10. A method of making an abrasive wheel comprising assembling aplurality of abrasive strips to form an annulus; and winding adhesivelycoated filamentary material adjacent at least one face of said annulusbetween the inner and outer peripheries thereof, the convolutions ofsaid material being bonded to one another and to the sides of saidstrips.

11. The method set forth in claim 10 including passing an anchor memberthrough each of said strips during the assembly thereof.

12. The method set forth in claim 10 wherein said filamentary materialis continuous and is dipped in an adhesive prior to being wound.

13. The method set forth in claim 12 wherein said filamentary materialis Wound under tension sulficient to cause said adhesive to be squeezedbetween adjacent ones of said strips.

14. The method set forth in claim 10 wherein said filamentary materialis Wound adjacent both faces of said annulus.

15. A method of making an abrasive wheel comprising: inserting an anchormember through an opening in each of a plurality of abrasive strips;arranging said strips in the form of an incomplete annulus and securingthe ends of the anchor member together by intertwining its ends;completing said annulus by adding abrasive strips having slots in theirinner ends so that the said slots receive the portions of the anchormember adjacent the intertwined ends and mask them; and adhesivelyjoining said strips to one another.

16. The method set forth in claim 15 in which the anchor member is wire.

17. The method set forth in claim 15 in which the ends of the anchormember are intertwined in a knot.

References Cited UNITED STATES PATENTS JAMES L. JONES, JR., PrimaryExaminer.

